Vibrations/rumbling at specific RPM range in 2.0 TDI engine

Hello,
'The engine in my Audi A3 Sportback 8P 2.0 TDI (125 KW) has been vibrating for some time now, specifically in the range of 1,400 RPM (1200-1600).'
'Doesn't this engine have balance shafts or anything like that that could change?'
It's not just an audible rumble, but it's actually something you can feel.

What probably isn't related to this, but I still want to mention:
Sometimes (!), after being idle for several hours, the engine doesn't start or starts very poorly, and initially runs extremely rough, almost like it's only running on 3 cylinders. Normally, it starts perfectly fine... No errors were found.
This summer, the fuel injection pumps were replaced as part of an Audi promotion.
After that, I noticed a high oil consumption (something I've never seen before in several TDI cars I've owned), almost 1 liter per 10,000 km!
Mileage is approximately 60,000 km.

Does anyone have any tips or suggestions for me about where these vibrations might be coming from?

And another question, I couldn't find a more suitable forum for it.
The coolant level warning light has been coming on frequently lately, even though the coolant level is sufficient.
Are there specified tolerance values for the sensor, or how can I determine if the problem is actually with the sensor and not, for example, due to a bad connection in the wiring?


Thank you very much!
Erka.

It sounds like there might be air in the system if it's not starting. In conjunction with the erratic engine running, one of the pressure sensors is likely leaking.

The values of the idle speed control would be interesting now. Perhaps something can be derived from that.

Sure, no problem.
It's strange because it usually starts up perfectly, and it also runs flawlessly at higher speeds. Likewise, the idle speed.
It's like that for any temperature reading around 1400, whether the engine is cold or warm...

Ah, and one more thing: Even when I'm easing off the accelerator, and the engine is going from 'high' to 'low' within this RPM range, it happens briefly.
That actually means it can't have anything to do with the PDs, right?

Best regards,
Erka.

Quote:

That actually means it can't have anything to do with the PDs, right?

This is speculation... first, you would need to run a diagnostic scan and obtain the values described above .

..... or we can ask the crystal ball .

Okay, then I guess I'll have to consult the repair shop after all...


Thank you in advance, and Merry Christmas to everyone .

Hmm, now the yellow warning light for the exhaust system is constantly illuminated...
(not a particulate filter)

Does anyone have a recommendation for a good workshop in the southern or southwestern part of Munich?
(Last time, I already paid almost 200 euros for them to find nothing.)

Greetings.
Erka.

Quote:

(I already paid almost 200 EUR last time, and they didn't find anything...)

...at that point, an investment in VCDS would have already paid off by half .